//  This file is part of YamlDotNet - A .NET library for YAML.
//  Copyright (c) Antoine Aubry and contributors

//  Permission is hereby granted, free of charge, to any person obtaining a copy of
//  this software and associated documentation files (the "Software"), to deal in
//  the Software without restriction, including without limitation the rights to
//  use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
//  of the Software, and to permit persons to whom the Software is furnished to do
//  so, subject to the following conditions:

//  The above copyright notice and this permission notice shall be included in all
//  copies or substantial portions of the Software.

//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
//  SOFTWARE.

using System;
using System.Collections.Generic;

namespace YamlDotNet.Core
{
    /// <summary>
    /// Generic queue on which items may be inserted
    /// </summary>
    [Serializable]
    public class InsertionQueue<T>
    {
        // TODO: Use a more efficient data structure

        private readonly IList<T> items = new List<T>();

        /// <summary>
        /// Gets the number of items that are contained by the queue.
        /// </summary>
        public int Count
        {
            get
            {
                return items.Count;
            }
        }

        /// <summary>
        /// Enqueues the specified item.
        /// </summary>
        /// <param name="item">The item to be enqueued.</param>
        public void Enqueue(T item)
        {
            items.Add(item);
        }

        /// <summary>
        /// Dequeues an item.
        /// </summary>
        /// <returns>Returns the item that been dequeued.</returns>
        public T Dequeue()
        {
            if (Count == 0)
            {
                throw new InvalidOperationException("The queue is empty");
            }

            T item = items[0];
            items.RemoveAt(0);
            return item;
        }

        /// <summary>
        /// Inserts an item at the specified index.
        /// </summary>
        /// <param name="index">The index where to insert the item.</param>
        /// <param name="item">The item to be inserted.</param>
        public void Insert(int index, T item)
        {
            items.Insert(index, item);
        }
    }
}